The most common operation performed by general surgeons in the United States is inguinal herniorrhaphy. Over 600,000 such procedures are performed annually. Lichtenstein and Shore first began using a plug composed of surgical mesh to treat femoral hernias and recurrent inguinal hernias in 1968. The plug consisted of a roll of surgical mesh that was coiled into a plug and inserted into the defect to fill the defect. The plug concept of treating a hernia developed by Lichtenstein and Shore was shown to be a simpler and more reliable repair than the previous conventional technique of suturing the defect to close. The rate of recurrent herniation proved to be very low compared to the former technique. The plug, however, lacks radial support to maintain its position within the defect.
Later, Gilbert and Rutkow began treating primary and recurrent hernias with an umbrella plug. A swath of surgical mesh was rolled into a cone shape and inserted into the tissue defect to occlude the void. While the plug provides more radial support than the plug of Lichtenstein and Shore, the plug, has certain disadvantages. The plug lacks the needed interior bulk to solidly fill the opening. Furthermore, the apex end of the conical mesh structure is inserted first into the defect, producing a sharp pointed edge which could cause irritation to the underlying tissue and discomfort to the patient. Since the plug is preformed and in a conical shape, it can only fill defects that are approximately its shape.
Fernandez in U.S. Pat. No. 5,147,374 disclosed a prosthetic patch for hernia repair. The patch is fabricated from a rolled up flat sheet of polypropylene or PTFE surgical mesh. The sheet of surgical mesh is rolled into a cylinder and bound together by catgut to hold its shape. One end of the rolled up mesh is cut with multiple slits to form flared out flaps. The flaps are sutured to a second sheet of surgical mesh. The patch is compressed into a cylindrical longitudinal structure and a trocar is used to insert it into the defect. Like the plug of Lichtenstein and Shore, this plug lacks radial support to maintain it in position and thus requires stitching of the covering mesh to the soft tissue to hold its position. The plug is preformed in a circular cross section and consequently does not conform well to variances in the contour of the defect.
The C.R. Bard Co. of Billerica, Mass. has introduced a preformed plug under the tradename PerFix Plug for hernia repair. The plug is cone shaped and fabricated from a layer of surgical mesh that is pleated to contact the contour of the defect. Multiple layers of a fill mesh provide bulk to fill the void. The plug is compressible, but because it is preformed and has a preset shape it does not exert significant outward radial force within the defect to prevent protrusion of material through the defect. While the plug has a more bunt tip at the apex of the cone than the plug of Gilbert and Rutkow, it still has a rather sharp tip that may cause irritation to the underlying tissue and discomfort to the patient.
What is clearly needed is a self-forming prosthesis for hernia repair that anatomically conforms well to the contours of a wide variety of defects, is easily insertable into the defect while having a blunt tip to seal the defect, minimize irritation and reduce discomfort in the patient after insertion.